as someone who worked for years at a modular store, and as a modular synth user for many years i think i can say for sure that stackables have never been a stable solution - they do work in feedback loops as a secondary layer, or when i transmit video into cv ins, but they can let you down sometimes with the interference mentioned above.
knock wood, i have never experienced issues when i was using buffered mults with cables though.
also sad to see that the overall trustworthiness and durability of patch cables have gone down the road pretty badly in the last few years (bending jacks, contact errors or complete dysfunctionality hits you just too early)
on a positive note, my doepfer patch cables are limited in their own ways (e.g. they do not fit in some ins or outs (a mechanical issue with the jack itself which can be addressed if you disassemble and adjust the jack), but god, they still deliver after 10 years of heavy use. never had to get rid of one except the 200cm cables.
maybe it could be time for lzx or some other makers to go for new quality standards - or just go back to the ones they used to have.